* if no record
* @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
* is sent when we want to turn off CS at the end of a transaction.
+ * @lock: mutex to ensure only one user of cros_ec_command_spi_xfer at a time
*/
struct cros_ec_spi {
struct spi_device *spi;
s64 last_transfer_ns;
unsigned int end_of_msg_delay;
+ struct mutex lock;
};
static void debug_packet(struct device *dev, const char *name, u8 *ptr,
/* Receive data until we see the header byte */
deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
- do {
+ while (true) {
+ unsigned long start_jiffies = jiffies;
+
memset(&trans, 0, sizeof(trans));
trans.cs_change = 1;
trans.rx_buf = ptr = ec_dev->din;
break;
}
}
+ if (ptr != end)
+ break;
- if (time_after(jiffies, deadline)) {
+ /*
+ * Use the time at the start of the loop as a timeout. This
+ * gives us one last shot at getting the transfer and is useful
+ * in case we got context switched out for a while.
+ */
+ if (time_after(start_jiffies, deadline)) {
dev_warn(ec_dev->dev, "EC failed to respond in time\n");
return -ETIMEDOUT;
}
- } while (ptr == end);
+ }
/*
* ptr now points to the header byte. Copy any valid data to the
int ret = 0, final_ret;
struct timespec ts;
+ /*
+ * We have the shared ec_dev buffer plus we do lots of separate spi_sync
+ * calls, so we need to make sure only one person is using this at a
+ * time.
+ */
+ mutex_lock(&ec_spi->lock);
+
len = cros_ec_prepare_tx(ec_dev, ec_msg);
dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
ktime_get_ts(&ts);
delay = timespec_to_ns(&ts) - ec_spi->last_transfer_ns;
if (delay < EC_SPI_RECOVERY_TIME_NS)
- ndelay(delay);
+ ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
}
/* Transmit phase - send our message */
ret = final_ret;
if (ret < 0) {
dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
- return ret;
+ goto exit;
}
/* check response error code */
dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n",
ec_msg->cmd, ptr[0]);
debug_packet(ec_dev->dev, "in_err", ptr, len);
- return -EINVAL;
+ ret = -EINVAL;
+ goto exit;
}
len = ptr[1];
sum = ptr[0] + ptr[1];
if (len > ec_msg->in_len) {
dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
len, ec_msg->in_len);
- return -ENOSPC;
+ ret = -ENOSPC;
+ goto exit;
}
/* copy response packet payload and compute checksum */
dev_err(ec_dev->dev,
"bad packet checksum, expected %02x, got %02x\n",
sum, ptr[len + 2]);
- return -EBADMSG;
+ ret = -EBADMSG;
+ goto exit;
}
- return 0;
+ ret = 0;
+exit:
+ mutex_unlock(&ec_spi->lock);
+ return ret;
}
static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
if (ec_spi == NULL)
return -ENOMEM;
ec_spi->spi = spi;
+ mutex_init(&ec_spi->lock);
ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
if (!ec_dev)
return -ENOMEM;